September 1, China’s official purchasing managers' index (PMI) for the manufacturing industry advanced slightly in August, but economists warned about risks for the country’s exports.

The PMI rose to 50.9 in August from a 28-month low of 50.7 in July, data from the China Federation of Logistics and Purchasing (CFLP) showed on Thursday.

Economists expected an increase to 51. A reading above 50 indicates expansion of the sector, while a reading below 50 indicates contraction.

"August's reading suggests economic growth is recovering gradually, but on the demand side there are still many uncertainties, and export growth will probably see a slowdown in the future," CFLP analyst Zhang Liqun said in a statement.

The new export orders sub-index fell to 48.3 from 50.4 in July, the first contraction since April 2009.

Economists said the weak exports reading could be an omen for the export-dependent economy.

"It is a sign that China was affected by turbulent global markets in August," said Standard Chartered economist Li Wei.

Meanwhile the purchasing price index, a measure of input costs, picked up by 0.9 percentage points from a month earlier to 57.2, reflecting looming inflationary pressures in the economy.